Down-regulation of STAT3 enhanced chemokine expression and neutrophil recruitment in biliary atresia

Biliary atresia (BA) is an immune-related disorder and signal transducer and activator of transcription 3 (STAT3) is a key signalling molecule in inflammation. The present study was designed to clarify the function of STAT3 in BA. STAT3 expression was examined in patients and a mouse BA model in which STAT3 levels were further altered with a specific inhibitor or activator. Neutrophil accumulation and the levels of the neutrophil chemoattractants (C-X-C motif) ligand 1 (CXCL1) and IL-8 were determined. The effects of STAT3 inhibition on IL-8 expression were examined in human biliary epithelial cell (BEC) cultures. Functional changes in liver STAT3+ neutrophils in the mouse model were analysed with 10× single cell RNA-seq methods. Results showed STAT3 and p-STAT3 expression was reduced in BA liver tissue compared with control samples. Administration of a STAT3 inhibitor increased jaundice and mortality and reduced body weight in BA mice. In contrast, the STAT3 activator ameliorated BA symptoms. Extensive neutrophil accumulation together with CXCL1 up-regulation, both of which were suppressed by an anti-CXCL1 antibody, were observed in the STAT3 inhibitor-treated group. Recombinant IL-8 administration increased disease severity in BA mice, and the STAT3 activator had the reverse effect. Inhibiting STAT3 increased apoptosis of human BECs together with up-regulated IL-8 expression. RNA-seq analysis revealed reduced the numbers of STAT3 expressing neutrophil in BA which was accompanied by marked enhanced interferon-related antiviral activities. In conclusion, STAT3 reduction, enhanced IL-8 and CXCL1 expression and promoted the accumulation of interferon-responsive neutrophils resulting in BEC damage in BA.

A59 A strategy to studying zoonotic infectious diseases

An increasing number of zoonotic viruses have been detected in animals, especially in poultry species. Understanding the diversity of zoonotic infections and the local behavior helps to characterize the pathogen diversity in human and animals and predict the risk of pathogen spill-over from animals to human. Vietnam is considered, along with other countries in Southeast Asia, as a hotspot for zoonotic viruses. In Vietnam, domestic animals are typically farmed in close proximity to humans, which may increase the risk of transmission of zoonotic pathogens. Our previous studies found the presence of some zoonotic viruses (e.g. rotavirus group A, hepatitis E virus) in domestic pigs. However, the risk of pathogenic transmission from domestic animals to humans has not been determined. Detailed genomic sequence data may help to track the origin and evolution of zoonotic pathogens. To understand the origins and emergence of zoonotic infections in people, who have regular contact with animals, we will investigate the viral diversity in farmers and domestic animals in their farm, using high-throughput sequencing technique. Viral RNA was extracted from pooled fecal samples of 30 farmers and 50 pigs, and used as input for SureSelect target enrichment and Illumina MiSeq sequencing.

The Toronto Western Hospital Catheter: One Center's Experience and Review of the Literature

Background

We report our center's experience with the Toronto Western Hospital (TWH) catheter, and discuss our catheter survival and complication rates.

Methods

Retrospective chart review of patients receiving peritoneal dialysis therapy via a TWH catheter. Catheter complication rates of peritonitis, exit site infection, obstruction, leak, and malfunction were assessed. A catheter was considered failed if removed because of exit site infection, obstruction, or malfunction. All other catheters, even if removed for other reasons, were considered censured. Survival was defined as the period from insertion to failure or censure date, and reported using Kaplan Meier analysis.

Results

192 patients with a total of 208 TWH catheters (4,845.3 catheter months) were analyzed. Our overall 1- and 3-year catheter survival rates were identical at 0.9182. Our catheter complication rates (expressed as number of catheter months per event) were 31.3 for peritonitis, 42.9 for exit site infection, 72.3 for obstruction, 538.4 for malfunction, and 969.1 for catheter leak. Our findings were similar to those reported in the literature for TWH and other peritoneal catheters.

Is congenital pulmonary airway malformation really a rare disease? Result of a prospective registry with universal antenatal screening program

BACKGROUND

Congenital pulmonary airway malformation (CPAM) is an increasingly recognized disease with potential mortality. Owing to limited published studies, the true incidence is yet to be determined. We carried out this prospective study with the aim to estimate its true incidence on a population basis.

METHODS

An antenatal ultrasonography program was implemented since 2009. Fetuses with suspected intra-thoracic lesions were monitored by regular follow-ups. Antenatal course, postnatal outcomes, and other demographics were compared to those of patients with CPAM in the previous decades (1989-2008). The incidence of CPAM was calculated in different periods.

RESULTS

66 CPAM patients were identified between 2009 and 2014 with 62 patients being detected by antenatal scan. In contrast, 45 patients were identified between 1989 and 2008 with 27 patients being detected antenatally. The incidence rate during the past and recent period was estimated as ~1 in 27,400 and ~1 in 7200 live births, respectively (p = 0.024).

CONCLUSION

With increasing awareness of clinicians and the universal use of latest ultrasound technology, it is likely that more CPAM cases will be detected in the future. Here, we presented our best estimated incidence rate of CPAM, yet only a larger scale study can reveal its true incidence.

Silver containing hydrofiber dressing promotes wound healing in paediatric patients with partial thickness burns

INTRODUCTION

Burn injury is one of the most common reasons for admission in paediatric population. There is currently no international consensus on the best wound dressing material. Aquacel Ag, a new silver containing hydrofiber dressing material has been reported to produce good clinical results. Yet, only a limited number of studies exist in the paediatric population. This study aims to review our experience of burn management over the past 5 years and to evaluate the effectiveness of Aquacel Ag in the management of partial thickness burns.

METHODS

A retrospective review of all patients admitted for burn injury between January 2010 and December 2014 was conducted. Patients' demographics, mechanism of injury, body surface areas involved, treatment applied, and clinical outcomes were analyzed. Patients with superficial injury, full thickness burns that required surgical debridement, burn area less than 2 % or more than 25 % of total body surface area, or incomplete clinical data were excluded from the comparative study.

RESULTS

A total of 119 patients were identified. 114 (96 %) was due to domestic injury, of which 108 (91 %) was food-related. The most commonly affected areas were limbs (n = 89, 74.8 %), followed by trunk (n = 62, 74.8). 84 patients fulfilled the inclusion criteria and were recruited into the study. 31 patients received Aquacel Ag dressing and 53 patients received standard paraffin gauze dressing. The two groups showed no statistical difference in age, sex, percentage of total body surface area involved, and infection rate. Outcomes of patients treated with Aquacel Ag were compared with patients treated with standard dressing. The mean hospital stay was significantly shorter for the Aquacel Ag group (14.26 vs 23.45, p = 0.045). Aquacel Ag group required much less frequent dressing change (5.67 vs 20.59, p = 0.002). 5 patients in standard dressing group developed hypertrophic scar and required prolonged pressure garment, whereas only one hypertrophic scar was observed in the Aquacel Ag group.

CONCLUSION

Aquacel Ag appears to promote early burn wound healing with less hypertrophic scar formation.

The feasibility and efficacy of multi-channel intraluminal impedance monitoring in children

INTRODUCTION

The diagnosis of gastro-oesophageal reflux is currently based on clinical presentation and oesophageal pH monitoring. In recent years, the use of multi-channel intraluminal impedance (MII) monitoring has gained increasing attention in the adult population. However, its use in the paediatric population is still in the developing stage with only limited number of publications. This study aims to review our early experience of MII application in children.

METHODS

A retrospective study of all patients who underwent MII monitoring between 2011 and 2014 at a tertiary referral centre was performed. Patients' medical records were reviewed with demographic data extracted. Number of reflux episodes and other MII parameters were analysed.

RESULTS

In total, 34 patients were identified during the study period, with 20 males and 14 females. Indication for study included previous aspiration pneumonia (n = 13), persistent reflux or vomiting symptom (n = 10) and as part of routine assessment before gastrostomy (n = 11). At the time of study the average age was 69 months (range 9-216 months). 28 patients showed significant gastro-oesophageal reflux. On average patient has 36.1 acidic and 22.3 non-acidic reflux episodes during the 24 h monitoring period. Non-acidic reflux accounts for 38.1 % of the overall reflux episodes. The sensitivity of MII monitoring to detect reflux was higher compared to conventional pH study (73 vs 50 %, p = 0.1).

CONCLUSION

MII monitoring is safe and feasible in children. Non-acid reflux should not be underestimated in paediatric population. MII appears to be more sensitive than conventional pH monitoring in our study, but its true significance is yet to be confirmed by larger study in the future.

The effects of the novel SHIP1 activator AQX-1125 on allergen-induced responses in mild-to-moderate asthma

BACKGROUND

SH2-containing inositol-5'-phosphatase 1 (SHIP1) is an endogenous inhibitor of the phosphoinositide-3-kinase pathway that is involved in the activation and chemotaxis of inflammatory cells. AQX-1125 is a first-in-class, oral SHIP1 activator with a novel anti-inflammatory mode of action.

OBJECTIVE

To evaluate the effects of AQX-1125 on airway responses to allergen challenge in mild-to-moderate asthmatic patients.

METHODS

A randomized, double-blind, placebo-controlled, two-way crossover study was performed in 22 steroid-naïve mild-to-moderate asthmatics with a documented late-phase response to inhaled allergen (LAR). AQX-1125 (450 mg daily) or placebo was administered orally for 7 days. Allergen challenge was performed on day 6 (2 h postdose), followed by methacholine challenge (day 7), and induced sputum collection and fractional exhaled nitric oxide (FeNO).

RESULTS

AQX-1125 significantly attenuated the late-phase response compared with placebo (FEV1 4-10 h: mean difference 150 mL, 20%; P = 0.027) and significantly increased the minimum FEV1 during LAR (mean difference 180 mL; P = 0.014). AQX-1125 had no effect on the early-phase response. AQX-1125 showed a trend in reduction of sputum eosinophils, neutrophils and macrophages although this did not achieve significance as there were only 11 paired samples for analysis. There was no effect on methacholine responsiveness or FeNO. Pharmacokinetic data showed AQX-1125 was rapidly absorbed with geometric mean Cmax and AUC0-24 h values of 1417 ng/mL and 16 727 h ng/mL, respectively. AQX-1125 was well tolerated, but mild GI side-effects (dyspepsia, nausea and abdominal pain) were described in 4/22 subjects on active treatment. These side-effects were mild self-limiting, required no further treatment and did not lead to discontinuation of therapy.

CONCLUSION AND CLINICAL RELEVANCE

AQX-1125, a novel oral SHIP1 activator, significantly reduces the late response to allergen challenge, with a trend to reduce airway inflammation. AQX-1125 was safe and well tolerated and merits further investigation in inflammatory disorders.

Role of polymorphisms of the inflammatory response genes and DC-SIGNR in genetic susceptibility to SARS and other infections

1. A genetic risk-association study involving more than 1200 subjects showed individuals homozygous for L-SIGN tandem repeats are less susceptible to SARS infection. 2. This was supported by in vitro binding studies that demonstrated homozygous L-SIGN, compared to heterozygous, had higher binding capacity for SARS coronavirus (SARS-CoV), with higher proteasome-dependent viral degradation. In contrast, homozygous L-SIGN demonstrated lower binding capacity for HIV1-gp120.3. Genetic-association studies for single nucleotide polymorphisms of the inflammatory response genes, namely TNF-alpha, INF-alpha, INF-beta, INF-gamma, IL1-alpha, IL1-beta, IL-4, IL-6 and iNOS, failed to show a significant association with SARS clinical outcomes or susceptibility.

A hepaticojejunostomy: technical errors with 'twists and turns'

Excision of a choledochal cyst followed by biliary reconstruction with a Roux-en-Y hepaticojejunostomy is the treatment of choice for type I and IV choledochal cysts. We present a rare complication which was identified 8 years after the original reconstructive surgery. Conventional imaging modalities failed to identify the pathology. Only a contrast enhanced CT scan supported by image rendering software allowed for the visualization of the underlying chronic obstruction of part of the mesentery.

Severe vitamin D deficiency in chronic renal failure patients on peritoneal dialysis

The aim of this study was to evaluate the prevalence of vitamin D deficiency in chronic renal failure (CRF) patients on peritoneal dialysis (PD) and to correlate the findings with various demographic and renal osteodystrophy markers.

METHOD

This cross-sectional, multicenter study was carried out in 273 PD patients with a mean age of 61.7 +/- 10.9 years and mean duration of PD 3.3 +/- 2.2 years. It included 123 female and 150 male patients from 20 centers in Greece and Turkey, countries that are on the same latitude, namely, 36-42 degrees north. We measured 25(OH)D3 and 1.25(OH)2D3 levels and some other clinical and laboratory indices of bone mineral metabolism.

RESULTS

Of these 273 patients 92% (251 patients) had vitamin D deficiency i.e. serum 25(OH)D3 levels less than 15 ng/ml, 119 (43.6%) had severe vitamin D deficiency i.e., serum 25(OH)D3 levels, less than 5 ng/ml, 132 (48.4%) had moderate vitamin D deficiency i.e., serum 25(OH)D3 levels, 5-15 ng/ml, 12 (4.4%) vitamin D insufficiency i.e., serum 25(OH)D3 levels 15 - 30 ng/ml and only 10 (3.6%) had adequate vitamin D stores. We found no correlation between 25(OH)D3 levels and PTH, serum albumin, bone alkaline phosphatase, P, and Ca x P. In multiple regression analyses, the independent predictors of 25(OH)D3 were age, presence of diabetes (DM-CRF), levels of serum calcium and serum 1.25(OH)2D3.

CONCLUSION

We found a high prevalence (92%) of vitamin D deficiency in these 273 PD patients, nearly one half of whom had severe vitamin D deficiency. Vitamin D deficiency is more common in DM-CRF patients than in non-DM-CRF patients. Our findings suggest that these patients should be considered for vitamin D supplementation.

N-Acetylglucosamine Reduces Inflammatory Response during Acute Peritonitis in Uremic Rats

BACKGROUND

Peritoneal dialysis (PD) induces intraperitoneal inflammation and that process may be uremia. The goal of this study is to evaluate the effect of uremia on the kinetics of peritonitis and furthermore test the anti-inflammatory potential of N-acetylglucosamine (NAG) in a uremic environment.

METHODS

Experiments were performed on healthy Wistar rats and on animals with impaired renal function. Acute PD was performed in all animals with dialysis fluid containing either glucose (GLU) or NAG as osmotic solutes. Peritonitis was induced by addition of lipopolysaccharide from Escherichia coli (LPS) to the dialysis fluid. Transperitoneal transport of water and solutes as well as intraperitoneal and systemic inflammation were evaluated.

RESULTS

Uremia reduces peritoneal permeability to total protein during peritonitis (-33% vs. control, p < 0.001) and increases net ultrafiltration (+2.5 +/- 2.2 vs. -2.7 +/- 3.2 ml in control, p < 0.001). In uremic rats with peritonitis, reduced dialysate levels of the following inflammatory mediators were detected as compared to healthy animals: MCP-1 (-15%, p < 0.01); IL-1beta (-53%, p < 0.001), and elastase (-28%, p < 0.02). In the serum of uremic rats, the increase in TNFalpha and MCP-1 concentrations was smaller than in control rats: -44% (p < 0.02) and -39% (p < 0.001), respectively. NAG used as an osmotic solute in rats with preserved renal function decreases intraperitoneal and systemic inflammation during acute peritonitis. Drained dialysate volume was increased in the NAG group by 32% (p < 0.001) and transperitoneal loss of protein was reduced by 21% (p < 0.002). When NAG was used as the osmotic solute instead of GLU, intraperitoneal inflammation in uremic animals was further reduced: TNFalpha (-40%, p < 0.05); IL-1beta (-49%, p < 0.005); MCP-1 (-21%, p < 0.005). The presence of NAG also reduced the increased blood level of IL-1beta (-47%,p < 0.02) and MCP-1 (-36%, p < 0.02).

CONCLUSIONS

Intensity of acute peritonitis is reduced during uremia. NAG exerts a systemic and peritoneal anti-inflammatory action under conditions of uremia that confirms the potential use of this compound as an osmotic agent in the PD fluids that also decreases inflammation.

N-Acetylglucosamine – An Osmotic Solute for Peritoneal Dialysis without Inducing Hyperinsulinemia

METHODS

N-Acetylglucosamine (NAG) was compared to glucose as an osmotic solute during peritoneal dialysis in rats. The effect of the tested solutes on blood glucose and insulin levels during dialysis was evaluated.

RESULTS

During 6-hour exchange with NAG (220 mmol/l) solution, the dialysate volume was higher than in rats dialyzed with fluid containing glucose (220 mmol/l; GLU: 34.5 +/- 1.7 vs. 32.8 +/- 1.1 ml, respectively; p < 0.05). The peritoneal permeability to protein (D/S x 1,000) was lower in the NAG group (9.7 +/- 2.5 vs. 16.3 +/- 5.6 in GLU; p < 0.02). Dialysis with GLU-based solution resulted in hyperglycemia up to 180 +/- 39 mg/dl; in the NAG group the increase in the blood glucose level was moderate (up to 91 +/- 9 mg/dl; p < 0.001). Dialysis with GLU fluid caused an increase in blood insulin level by 53.2 +/- 62.4 pmol/l, whereas the insulin blood concentration in NAG-treated animals was increased by 5.0 +/- 5.4 pmol/l (p < 0.001).

CONCLUSIONS

NAG is more effective than GLU osmotic solute during peritoneal dialysis and it reduces peritoneal permeability to protein. Dialysis with NAG results in lower hyperglycemia and hyperinsulinemia, both effects are favorable in diabetic peritoneal dialysis patients.

Effect of iron sucrose on human peritoneal mesothelial cells

BACKGROUND

Iron supplementation is often required in uraemic patients with anaemia. Peritoneal cavity was proposed as an alternative intravenous route for iron infusion in patients treated with peritoneal dialysis. We studied the effect of iron sucrose (Venofer) on the function of human peritoneal mesothelial cells maintained in in vitro culture.

MATERIALS AND METHODS

In in vitro experiments on human peritoneal, the mesothelial effect of elemental iron (in conc. 0.0001-1 mg mL-1) present in Venofer on their viability, growth and synthesis of IL-6 was studied. Additionally we evaluated with a fluorescent probe (2',7'-dichlorodihydro-fluorescein diacatate) generation of reactive oxygen species in cells exposed to iron sucrose. We also measured accumulation of iron in the cytoplasm of mesothelial cells after their in vitro exposure to Venofer.

RESULTS

In in vitro conditions iron induces a dose-dependent inhibition of viability of the mesothelial cells as reflected by inhibition of the cells growth by 34% at Fe 0.1 mg mL-1 vs. control (P < 0.05) increased release of lactate dehydrogenase (LDH) from the cytosol: 67.1 +/- 30.3 mU mL-1 at Fe 1 mg mL-1 vs. 7.9 +/- 6.4 in control group (P < 0.001), and reduced synthesis of IL-6: 209 +/- 378 pg mg-1 cell protein at Fe 1 mg mL-1 vs. 38674 +/- 4146 pg mg-1 cell protein in controls (P < 0.001). Cytotoxicity of iron towards mesothelial cells was enhanced in vitro when it was tested in presence of the dialysis fluid. Iron used in vitro at concentration 0.0001 mg mL-1 and greater induces generation of oxygen-derived free radicals in mesothelial cells. Furthermore, iron is taken by these cells and stored in their cytosol, resulting in stimulation of the intracellular generation of free radicals.

CONCLUSIONS

We conclude that iron used in the form of iron sucrose is cytotoxic to human peritoneal mesothelial cells. Accumulation of iron sucrose within cytoplasm of these cells may lead to induction of its chronic cytotoxic effect.

Replacement of glucose with N-acetylglucosamine in peritoneal dialysis fluid-experimental study in rats

BACKGROUND

Glucose is still used as an osmotic solute in peritoneal dialysis fluids, despite evidence of its local (peritoneal) and systemic toxicities. However a constant search is underway for a new, more biocompatible osmotic solute for peritoneal dialysis fluids.

OBJECTIVE

The present study evaluated N-acetylglucosamine (NAG) in a concentration of 220 mmol/L as an alternative to glucose for the osmotic solute in peritoneal dialysis fluid, during chronic peritoneal dialysis in rats.

METHODS

For 8 weeks, male Wistar rats were infused with glucose-based or NAG-based dialysis fluid. Intraperitoneal inflammation and peritoneal permeability and morphology were evaluated in all rats during the study.

RESULTS

Repeated intraperitoneal infusion of the NAG-based dialysis fluid resulted in a weaker intra-abdominal inflammatory reaction as compared with the reaction in rats infused with glucose-based dialysis solution. At the end of the study, the concentration of hyaluronan in the peritoneal interstitium obtained from NAG-treated rats was higher than that found in the interstitium taken from animals exposed to dialysis fluid containing glucose. Also, peritoneal permeability to total protein was lower in NAG-treated rats.

CONCLUSION

As an alternative to glucose, NAG used for the osmotic solute in peritoneal dialysis solution decreases the intraperitoneal inflammatory reaction induced by the process of peritoneal dialysis and, indirectly (owing to the increased hyaluronan content in the peritoneal interstitium), diminishes peritoneal permeability to protein.

Chronic peritoneal dialysis in octogenarians

BACKGROUND

During the past few decades the pattern of end-stage renal failure disease has changed with increasing number of elderly patients admitted for dialysis. In spite of their increasing number, little is known about the optimal mode of therapy of the 'old old' (those >or=80 years) patients.

METHODS

In this retrospective study, we analysed the results of treatment of 31 non-institutionalized 'old old' patients at Toronto Western Hospital (17) and Scarborough General Hospital (14) and seven institutionalized patients in chronic care, Riverdale Hospital. The patients were on CAPD with Twin-bag Baxter (28) or Home Choice, Baxter or Fresenius CCPD system (10). Patients were screened at the CAPD clinic when routine blood investigations were done. Patient and technique survival, initial and final laboratory data (last visit or before death) and complications related/unrelated to dialysis method are presented.

RESULTS

Multiple comorbid conditions were present at the start of the treatment and new added during treatment; very few were dialysis-related. The majority of non-institutionalized patients required assistance of home-care nurse to perform dialysis. Peritonitis (1/28.6 patient months) and exit-site infection rate (1/75.1 patient months) were low and responded to treatment. Incidence of peritonitis was higher among institutionalized debilitated patients (1/5.3 patient months). Incidence of hospitalization was 1/14.7 patient months and patients spent in hospital 7.5 days/patient year. Forty-seven per cent of patients survived 24 months; 39% survived 30 months. Technique survival was 91.5% at 12 months and 81.4% at 30 months. Poor appetite and malnutrition were frequent among very old patients. Patients and their families were motivated for treatment and discontinuation of dialysis was not higher than described elsewhere in literature.

CONCLUSIONS

This study has demonstrated that chronic peritoneal dialysis could be recommended as a safe and suitable modality of treatment of end-stage renal failure in old old patients.

The early neural plate rules over the mesoderm

In this issue of Developmental Cell, Richard Harland and colleagues describe evidence that an inductive interaction between the neural plate and the paraxial mesoderm regulates somite development and somite size.

Genetic and developmental analysis of X-inactivation in interspecific hybrid mice suggests a role for the Y chromosome in placental dysplasia

It has been shown previously that abnormal placental growth, i.e., hyper- and hypoplasia, occurs in crosses and backcrosses between different mouse (Mus) species. A locus that contributes to this abnormal development has been mapped to the X chromosome. Unexpectedly, an influence of fetal sex on placental development has been observed, in that placentas attached to male fetuses tended to exhibit a more pronounced phenotype than placentas attached to females. Here, we have analyzed this sex dependence in more detail. Our results show that differences between male and female placental weights are characteristic of interspecific matings and are not observed in intraspecific Mus musculus matings. The effect is retained in congenic lines that contain differing lengths of M. spretus-derived X chromosome. Expression of the X-linked gene Pgk1 from the maternal allele only and lack of overall activity of two paternally inherited X-linked transgenes indicate that reactivation or lack of inactivation of the paternal X chromosome in trophoblasts of interspecific hybrids is not a frequent occurrence. Thus, the difference between male and female placentas seems not to be caused by faulty preferential X-inactivation. Therefore, these data suggest that the sex difference of placental weights in interspecific hybrids is caused by interactions with the Y chromosome.

Stabilized plasmid-lipid particles for systemic gene therapy

The structure of 'stabilized plasmid-lipid particles' (SPLP) and their properties as systemic gene therapy vectors has been investigated. We show that SPLP can be visualized employing cryo-electron microscopy to be homogeneous particles of diameter 72 +/- 5 nm consisting of a lipid bilayer surrounding a core of plasmid DNA. It is also shown that SPLP exhibit long circulation lifetimes (circulation half-life >6 h) following intravenous (i.v.) injection in a murine tumor model resulting in accumulation of up to 3% of the total injected dose and concomitant reporter gene expression at a distal (hind flank) tumor site. In contrast, i v. injection of naked plasmid DNA or plasmid DNA-cationic liposome complexes did not result in significant plasmid delivery to the tumor site or gene expression at that site. Furthermore, it is shown that high doses of SPLP corresponding to 175 microg plasmid per mouse are nontoxic as assayed by monitoring serum enzyme levels, whereas i.v. injection of complexes give rise to significant toxicity at dose levels above 20 microg plasmid per mouse. It is concluded that SPLP exhibit properties consistent with potential utility as a nontoxic systemic gene therapy vector.

X inactivation in the mouse embryo deficient for Dnmt1: distinct effect of hypomethylation on imprinted and random X inactivation

It has been suggested that DNA methylation plays a crucial role in genomic imprinting and X inactivation. Using DNA methyltransferase 1 (Dnmt1)-deficient mouse embryos carrying X-linked lacZ transgenes, we studied the effects of genomic demethylation on X inactivation. Based on the expression pattern of lacZ, the imprinted X inactivation in the visceral endoderm, a derivative of the extraembryonic lineage, was unaffected in Dnmt1 mutant embryos at the time other imprinted genes showed aberrant expression. Random X inactivation in the embryonic lineage of Dnmt1 mutant embryos, however, was unstable as a result of hypomethylation, causing reactivation of, at least, one lacZ transgene that had initially been repressed. Our results suggest that maintenance of imprinted X inactivation in the extraembryonic lineage can tolerate extensive demethylation while normal levels of methylation are required for stable maintenance of X inactivation in the embryonic lineage.

Suppression of cytokine production and cell adhesion molecule expression in human monocytic cell line THP-1 by Tripterygium wilfordii polysaccharide moiety

Extracts of the vine-like plant Tripterygium wilfordii (TW) have been widely used in China as an immunosuppressant and anti-inflammatory drug for the treatments of rheumatoid arthritis, lupus erythematosus and other inflammatory disorders. In this study the molecular mechanisms of action of three TW extracts (ethanol, aqueous, polysaccharide) on the expression of inflammatory cytokines and adhesion molecules were investigated by RT-PCR and immunofluorescence binding techniques. The lipopolysaccharide (LPS)-mediated stimulatory effects of tumor necrosis factor-alpha (TNF-alpha) cytokine production and cell adhesion molecule (CD11c, CD18, CD14, CD54) expression in human monocytic THP-1 cells were modulated by treatments of the TW extracts or tacrolimus (FK506). The TW polysaccharide moiety exhibited more profound immunosuppressive properties than the aqueous and ethanol extracts. Biochemical characterization of the polysaccharide moiety revealed a major molecular weight of 22 kDa (viz. PSP22). The PSP22 was found to be a potential immunosuppressant that manifests the necessary immunomodulating properties.

Stabilized plasmid-lipid particles: pharmacokinetics and plasmid delivery to distal tumors following intravenous injection

A previous study has shown that plasmid DNA can be encapsulated in lipid particles (SPLP, "stabilized plasmid lipid particles") of approximately 70 nm diameter composed of 1,2-dioleoyl-3-phosphatidyl-ethanolamine (DOPE), the cationic lipid N,N-dioleoyl-N,N-dimethylammonium chloride (DODAC) and poly(ethylene glycol) conjugated to ceramide (PEG-Cer) using a detergent dialysis process (Wheeler et al. (1999) Gene Therapy 6, 271-281). In this work we evaluated the potential of these SPLPs as systemic gene therapy vectors, determining their pharmacokinetics and the biodistribution of the plasmid and lipid components. It is shown that the blood clearance and the biodistribution of the SPLPs can be modulated by varying the acyl chain length of the ceramide group used as lipid anchor for the PEG polymer. Circulation lifetimes observed for SPLPs with PEG-CerC14 and PEG-CerC20 were t(1/2) = approximately 1 and approximately 10 h, respectively. The SPLPs are stable while circulating in the blood and the encapsulated DNA is fully protected from degradation by serum nucleases. The accelerated clearance of SPLPs with PEG-CerC14 is accompanied by increased accumulation in liver and spleen as compared to PEG-CerC20 SPLPs. Delivery of intact plasmid to liver and spleen was detected. Significant accumulation (approximately 10% of injected dose) of the long circulating SPLPs with PEG-CerC20 in a distal tumor (Lewis lung tumor in the mouse flank) was observed following i.v. application and delivery of intact plasmid to tumor tissue at approximately 6% injected dose/g tissue is demonstrated.

The effect of N-acetylglucosamine as a substrate for in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts

The effect of N-acetylglucosamine (NAG) on in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts was studied. In contrast to isosmotic concentrations of glucose, NAG increases the synthesis of hyaluronan by mesothelial cells and fibroblasts in a dose-dependent manner. This effect of NAG can be demonstrated in the presence of increased glucose levels in a medium, or in a medium mixed with effluent dialysate obtained from continuous ambulatory peritoneal dialysis (CAPD) patients. Glucose inhibits synthesis of sulphated glycosaminoglycans by peritoneal mesothelial cells and fibroblasts, whereas NAG stimulates their production. Our results demonstrate that NAG is an effective stimulator of the in vitro glycosaminoglycans synthesis by human peritoneal mesothelial cells and fibroblasts.

Residual bladder dysfunction 2 to 10 years after acute transverse myelitis

OBJECTIVE

Acute transverse myelitis (ATM) is a relatively rare condition in children. The recovery rate is reported to be generally complete. In the current study, the long-term urological outcome of children with ATM was assessed.

METHODOLOGY

The medical records of children with ATM admitted to Queen Mary Hospital, Hong Kong, over the last 15 years, were reviewed.

RESULTS

The median age of the five children with ATM at the time of onset was 6 years (range = 2-12 years). The median length of follow up was 5 years (2-10 years). Four children recovered completely from paraparesis; two had no urinary symptoms with normal micturition. However, video-urodynamic studies 3 years after the acute onset revealed that four out of the five children, including one without any urinary symptom, suffered from residual bladder dysfunction - two from contractile neurogenic bladder and two from intermediate type of neurogenic bladder.

CONCLUSION

Residual bladder dysfunction is common in children suffering from ATM despite improvement of paraparesis and apparent lack of urological symptoms. Long-term follow up of urological function in these patients is recommended.

Effect of N-acetylglucosamine on function of peritoneal leukocytes

OBJECTIVE

To compare effects of N-acetylglucosamine (NAG)-based and glucose-based dialysis fluids on the function of peritoneal leukocytes in conditions of peritoneal dialysis.

DESIGN

In vitro experiments on ex vivo isolated rat peritoneal leukocytes.

MATERIALS

Peritoneal leukocytes were isolated from rats on chronic peritoneal dialysis. On alternate days, fluid exchanges were performed with NAG-based or glucose-based dialysis solutions. After a 4-hour dwell, dialysate was drained and peritoneal leukocytes were incubated in vitro +/- lipopolysaccharide (LPS). Production of nitrites (index of NO synthesis), tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and interferon gamma (IFN-gamma) by unstimulated or stimulated peritoneal leukocytes originating from NAG-based or glucose-based fluid was measured.

RESULTS

Dialysate cell count was lower during exchanges with NAG-based fluid (2113+/-615 cells/microL) as compared to glucose-based fluid (3643+/-1108 cells/microL; p < 0.01). Differential cell count was similar in both studied groups. Unstimulated peritoneal leukocytes from NAG-based dialysate produced more NO (nitrites) (0.65+/-0.07 micromol per 10(6) cells) than did cells from glucose-based dialysate (0.26+/-0.09 micromol per 106 cells, p < 0.01). Stimulated peritoneal leukocytes from NAG-based dialysate produced more cytokines than did cells from glucose-based dialysate: TNFalpha, 135.2+/-37.0 pg versus 70.2+/-21.8 pg per 10(6) cells respectively, p < 0.01; IL-1beta, 143.2+/-60.9 pg versus 99.1+/-22.4 pg per 10(6) cells respectively, p < 0.05; IFN-gamma, 16.2+/-12.5 pg versus 6.0+/-1.8 pg per 10(6) cells respectively, p < 0.01.

CONCLUSIONS

We demonstrated that rat peritoneal leukocytes exposed in vivo to NAG-based dialysis fluid have better ability to produce inflammatory mediators than do peritoneal leukocytes from the same donor, but exposed in vivo to glucose-based dialysis solution.

Liposomal lipid and plasmid DNA delivery to B16/BL6 tumors after intraperitoneal administration of cationic liposome DNA aggregates

The transfer of plasmid expression vectors to cells is essential for transfection after administration of lipid-based DNA formulations (lipoplexes). A murine i.p. B16/BL6 tumor model was used to characterize DNA delivery, liposomal lipid delivery, and gene transfer after regional (i.p.) administration of free plasmid DNA and DNA lipoplexes. DNA lipoplexes were prepared using cationic dioleoyldimethylammonium chloride/dioleoylphosphatidylethanolamine (50:50 mol ratio) liposomes mixed with plasmid DNA (1 microgram DNA/10 nmol lipid). The plasmid used contained the chloramphenicol acetyltransferase gene and chloramphenicol acetyltransferase expression (mU/g tumor) was measured to estimate transfection efficiency. Tumor-associated DNA and liposomal lipid levels were measured to estimate the efficiency of lipid-mediated DNA delivery to tumors. Plasmid DNA delivery was estimated using [3H]-labeled plasmid as a tracer, dot blot analysis, and/or Southern analysis. Liposomal lipid delivery was estimated using [14C]-dioleoylphosphatidylethanolamine as a liposomal lipid marker. Gene expression in the B16/BL6 tumors was highly variable, with values ranging from greater than 2,000 mU/g tumor to less than 100 mU/g tumor. There was a tendency to observe enhanced transfection in small (<250 mg) tumors. Approximately 18% of the injected dose of DNA was associated with these small tumors 2 h after i.p. administration. Southern analysis of extracted tumor DNA indicated that plasmid DNA associated with tumors was intact 24 h after administration. DNA and associated liposomal lipid are efficiently bound to tumors after regional administration; however, it is unclear whether delivery is sufficient to abet internalization and appropriate subcellular localization of the expression vector.

Cationic lipid-mediated transfection of cells in culture requires mitotic activity

Cationic lipid-based delivery systems such as lipoplexes or stabilized plasmid-lipid particles (SPLP) represent a safer alternative to viral systems for gene therapy applications. We studied the impact of cell cycle status on the efficiency of transfection of human ovarian carcinoma tumor cells using two cationic-lipid based delivery systems. Cells arrested in the G1 phase of the cell cycle by treatment with aphidicolin were compared with an asynchronous dividing population of cells. Treatment of the cells with aphidicolin had no effect on the rate of internalization of the lipid formulated DNA or on the level of gene expression observable in stably transfected cells. However, cells treated with aphidicolin exhibited 20-fold lower reporter gene activity than asynchronous control cells upon incubation with lipoplexes. When cells arrested in the G1 phase were allowed to proceed through the cell cycle in the presence of the lipoplex or SPLP, transgene expression was found to coincide with the transition of cells from the G2/M phase into the G1 phase of the subsequent cell cycle. In addition, higher levels of reporter gene expression were observed when the cells were incubated with lipoplexes or SPLP during, or just before, mitosis. These results suggest that it may be possible to augment cationic lipid-mediated transfection by manipulating the cell cycle status of the target cells.

N-acetylglucosamine changes permeability of peritoneum during chronic peritoneal dialysis in rats

OBJECTIVE

To evaluate the effect of supplementation of dialysis fluid with N-acetylglucosamine (NAG) on the permeability of peritoneum during chronic peritoneal dialysis in rats.

DESIGN

Experiments were performed on rats with surgically implanted peritoneal catheters. Dialysis solution [Dianeal 1.5% (Baxter, Deerfield, IL, U.S.A.) supplemented with either NAG 50 mmol/L or glucose 50 mmol/L (control)] was infused intraperitoneally twice, every day, for 8 weeks. Peritoneal equilibration tests (PET) were performed in all animals at the beginning of the study and after 8 weeks of dialysis. Additionally, at the end of each week, dialysis solution infused in the morning was drained after 4 hours of intraperitoneal dwell. White blood cell count, creatinine, and total protein concentrations were measured in the effluent dialysate. After 8 weeks of dialysis, the morphology of the peritoneum was studied.

RESULTS

In rats exposed to dialysis fluid supplemented with NAG, peritoneal permeability to creatinine and proteins was reduced when compared to animals dialyzed with glucose solution. In NAG treated animals, staining with alcian blue for polyanions in the peritoneal interstitium was significantly stronger than in rats dialyzed with glucose solution.

CONCLUSIONS

Chronic peritoneal dialysis with dialysis solution supplemented with N-acetylglucosamine causes accumulation of glycosaminoglycans in the peritoneal interstitium, which results in a change of peritoneal permeability.

Pattern formation in the cerebellum of murine embryonic stem cell chimeras

The cerebellar cortex is subdivided into an elaborate, stereotyped array of transverse zones and parasagittal stripes. It has been speculated that (i) all Purkinje cells derive from 10 to 20 precursors allocated early in embryogenesis and (ii) that pattern formation is based on cell lineage restriction in the founder pool. These hypotheses have been tested by clonal analysis of embryonic stem cell chimeras. Neither speculation is supported: the analysis suggests that Purkinje cells derive from a founder population of > 102 precursors, and that neither cerebellar transverse developmental boundaries nor parasagittal stripes have a clonal origin. We conclude that early lineage restriction plays no role in cerebellar pattern formation.

High-dose intravenous immune globulin and the response to splenectomy in patients with idiopathic thrombocytopenic purpura

BACKGROUND

High-dose intravenous immune globulin produces a temporary rise in the platelet count in patients with idiopathic thrombocytopenic purpura. Splenectomy may also be effective, but it is not possible to predict which patients will have a good response. We hypothesized that the response to intravenous immune globulin predicts the response to splenectomy.

METHODS

We studied retrospectively 30 patients with idiopathic thrombocytopenic purpura who had first been treated with immune globulin and then undergone splenectomy. The responses to the two treatments were classified on the basis of the platelet count as poor (<50,000 per cubic millimeter), good (50,000 to 150,000 per cubic millimeter), or excellent (>150,000 per cubic millimeter).

RESULTS

All nine patients who had poor responses to intravenous immune globulin also had poor responses to splenectomy at one year. Of the 21 patients with good or excellent responses to intravenous immune globulin, 19 had good or excellent responses to splenectomy.

CONCLUSIONS

Patients with idiopathic thrombocytopenic purpura who have good or excellent responses to intravenous immune globulin are likely to have good or excellent responses to splenectomy, whereas patients who have poor responses to intravenous immune globulin are unlikely to have good or excellent responses to splenectomy.

The effect of regulatory sequence elements upon the initiation of DNA replication of the minute virus of mice

The minute virus of mice (MVM) genome is a linear single-stranded length of approximately 5000 nucleotides of DNA with unique terminal palindromic sequences at both ends. The left(3') hairpin is used to prime the initiation of DNA synthesis on parental single-strand DNA while the right (5') hairpin or stem-plus-arms structure can also prime the initiation of DNA synthesis during synthesis of dimer and higher oligomers as well as synthesis of progeny single strands. Previous studies have shown that if viral duplex DNA was input into an in vitro DNA replication system using extracts from uninfected HeLa cells, the 5' end of the molecule was able to form a hairpin and initiate DNA synthesis by DNA polymerase delta (Cossons et al. (1996), Virology 216, 258-264). In this study, the effect of the deletion of known cis-acting genetic elements upon the initiation of DNA replication was studied using a series of MVM mutants with deletions within the 5' terminal region. Mutants containing deletions of elements A (nucleotides 4489-4636), B (nucleotides 4636-4695), and either one or both of the 65-bp repeats (nucleotides 4720-4785 and 4785-4849) were used as template in the in vitro DNA replication system. When element A was deleted, the efficiency of initiation decreased significantly. Subsequent removal of element B, leaving just the two 65-bp repeats, restored levels of initiation back to those seen in the wild-type genome. In the absence of either A or B both 65-bp repeats were necessary for efficient initiation, and removal of one of these repeats caused a decrease in efficiency. Thus, element B appeared to have a negative regulatory effect (in the absence of element A), and element A appeared to have a positive regulatory effect, at least in the presence of element B. These data demonstrate, for the first time, a complex interaction between these cis-acting regulatory elements which can function as both positive or negative regulators in the initiation of MVM DNA replication.

Heterozygous endothelin receptor B (EDNRB) mutations in isolated Hirschsprung disease

Hirschsprung disease (HSCR, aganglionic megacolon) is a frequent congenital malformation regarded as a multigenic neurocristopathy. Two susceptibility genes have been recently identified in HSCR, namely the RET proto-oncogene and the endothelin B receptor (EDNRB) gene. Hitherto however, homozygosity for EDNRB mutations accounted for the HSCR-Waardenburg syndrome (WS) association. Here, we report heterozygous EDNRB missense mutations (G57S, R319W and P383L) in isolated HSCR. These data might suggest that EDNRB mutations could be dosage sensitive: heterozygosity would predispose to isolated HSCR with incomplete penetrance, while homozygosity would result in more complex neurocristopathies associating HSCR and WS features. In addition, the present data give further support to the role of the endothelin-signalling pathway in the development of neural crest-derived enteric neurons.

Pre-operative MRI of anorectal anomalies in the newborn period

Nine infants (six boys, three girls) with anorectal anomalies were examined in the immediate newborn period, prior to corrective surgery, with MRI. Three high, one intermediate and five low anomalies were found at MRI - one patient with a low lesion was subsequently found at surgery 2 months later to have a high anorectal anomaly. This infant had passed meconium per urethram soon after the MRI study, prompting the need for a protective colostomy and stressing the importance of a thorough clinical examination of babies with anorectal malformations. The MRI results and findings at surgery were in agreement in all other patients (n = 8). Hydronephrosis was evident in two and renal agenesis in one patient. Sacrococcygeal hypoplasia was found in two and two hemivertebrae in one infant. No spinal cord lesion was identified. One fistula was evident on MRI but four were later found at surgery. Uniformly hyperintense T 1 signal meconium was seen in all nine newborns, allowing for easy differentiation of rectal contents from rectal wall and the adjacent musculature. MRI can provide useful information regarding the development of the puborectal and external anal sphincter muscles, can help guide the pull-through procedure and help predict future continence pre-operatively in the newborn period.